title: Revisiting diastolic filling time as mechanistic insight for response to cardiac resynchronization therapy.
abstract: OBJECTIVE
  Intraventricular dyssynchrony and commonly associated prolonged atrioventricular conduction both reduce diastolic filling time (DFT), which can be improved by cardiac resynchronization therapy (CRT). Our aim was to investigate whether change in DFT corrected for RR interval (DFTC) after CRT might serve to assess the mechanistic response to CRT.
  
  
  RESULTS
  Echocardiography data of consecutive patients in sinus rhythm (n = 91) were studied before and 6 months after implantation. Mortality and heart failure hospitalization data were collected. Patients with vs. without DFTC increase after 6 months were compared. The programmed atrioventricular delay, percentage of biventricular pacing, and change in PR interval were similar in both groups. DFTC increase after 6 months reflected favourable reverse left ventricular remodelling and was significantly associated with freedom from death or heart failure admission (P = 0.008). In multivariate analysis including guideline criteria for CRT (i.e. QRS width, presence of left bundle branch block, and ejection fraction), interventricular mechanical delay, and Tei index, baseline DFTC was the strongest predictor of adverse outcome. Notably, while patients with impaired relaxation had a large and highly significant reduction in all-cause mortality and heart failure admissions when DFTC increased [hazard ratio (HR), 95% confidence interval (CI) = 0.24, 0.08-0.73; P = 0.012], this benefit was less pronounced and did not reach statistical significance in patients with pseudonormal or restrictive filling (HR, 95% CI = 0.64, 0.23-1.77; P = 0.388).
  
  
  CONCLUSIONS
  DFTC increase after CRT reflects favourable reverse remodelling and is associated with better clinical outcome.
authors.affiliation: Department of Cardiology, Ziekenhuis Oost-Limburg, Schiepse Bos 6, 3600 Genk, Belgium.
authors.forename: Frederik H
authors.initials: FH
authors.lastname: Verbrugge
authors.forename: David
authors.initials: D
authors.lastname: Verhaert
authors.forename: Lars
authors.initials: L
authors.lastname: Grieten
authors.forename: Matthias
authors.initials: M
authors.lastname: Dupont
authors.forename: Maximo
authors.initials: M
authors.lastname: Rivero-Ayerza
authors.forename: Philip
authors.initials: P
authors.lastname: De Vusser
authors.forename: Hugo
authors.initials: H
authors.lastname: Van Herendael
authors.forename: Rozette
authors.initials: R
authors.lastname: Reyskens
authors.forename: Pieter
authors.initials: P
authors.lastname: Vandervoort
authors.forename: Wai Hong Wilson
authors.initials: WH
authors.lastname: Tang
authors.forename: Wilfried
authors.initials: W
authors.lastname: Mullens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D054537:Atrioventricular Block / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000401:mortality; D003971:Diastole; D015150:Echocardiography, Doppler; D005260:Female; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission; D011237:Predictive Value of Tests; D020127:Recovery of Function; D012189:Retrospective Studies; D012307:Risk Factors; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling
keywords: Cardiac resynchronization therapy; Diastolic filling time; Heart failure; Outcome; Reverse remodelling